Enhanced Efficiency Fertilizers Manitoba Agronomists Conference December 16, 2009 by Clain Jones, Extension Soil Fertility Specialist and Kathrin Olson-Rutz, Research Associate clainj@montana.edu; 994-6076
Enhanced Efficiency Fertilizers EEFs Any fertilizer designed to: Increase fertilizer availability Decrease fertilizer losses 3 major methods of action Stabilized - alter soil microbial or enzymatic reactions Slow release - have additives which require chemical or biological decomposition to release nutrients Controlled release - a semipermiable coating, usually a polymer, regulates release
Questions Who sells EEFs? Who has used or recommended EEFs?
Objectives Explain types of EEFs Describe how they work Show their benefits and limitations
Leaching Plant Uptake Volatilization Denitrification Stabilized Urease Inhibitors N 2 and N 2 O NH 3 - NO 3 slow urea hydrolysis here, most common is NBPT Urea + NH 4 UAN - NO 2
Leaching Plant Uptake Volatilization Denitrification Stabilized Nitrification Inhibitors N 2 and N 2 O slow conversion to nitrate here NH 3 - NO 3 + NH 4 - NO 2 Urea UAN
Leaching Plant Uptake Volatilization Denitrification Slow and Controlled Release N 2 and N 2 O NH 3 - NO 3 + NH 4 - NO 2 Slow/control release here Urea UAN
Partial list of available stabilized EEFs Stabilized Nutrisphere-N (NSN) Agrotain Avail NSource NServe Instinct SuperU Nitamin Nfusion
Partial list of available controlled and slow release EEFs Controlled Release ESN Polyon PolyS Duration Slow Release NSure Nitroform Nutralene
% Nitrogen Uptake or Release Nutrient availability from ideal slow release fertilizer 100 80 60 40 Theoretical Nutrient Release Plant Uptake for Optimal Yield 20 0 0 20 40 60 80 100 Days After Emergence
water moves in through coating N release by polymer-coated fertilizers urea dissolves in prill N moves out through coating into soil solution Schematic adaptation and photo courtesy of Agrium, U.S. All rights reserved. collapsed prill biodegrades
Questions?
Under what growing conditions would you expect EEFs to work better? High potential volatilization loss coarse soils moist surface warm temps long time between application and incorporation High potential leaching coarse soils high moisture content/irrigation/rainfall
Cumlative N loss (% of Applied N) Effect of irrigation and NBPT on volatilization 18 16 14 12 10 8 6 4 0.8 inch irrigation on days 2 and 8 Rawluk 2000 Manitoba Urea Urea + irrigation NBPT- urea 2 0 NBPT-urea + irrigation 0 2 4 6 8 10 12 Days after N Fertilization
NBPT uses Can minimize urea volatilization for up to 14 days Buys time for rainfall, irrigation or mechanical incorporation to protect urea Warm weather top-dressing Cool weather broadcast
Yield Change with Spring-banded PCU over Conventional Urea (%) Effects of over-winter moisture conditions on effectiveness of PCU 16 14 Barley WHY? 12 Canola 10 Wheat 8 6 4 Grant & Downbenko 2008 spring banded PCU Saskatchewan 2 0-2 -4 Low Moisture High Moisture
Number of Comparisons Distribution of corn yield response to ESN 50 45 40 35 Average difference ESN vs. urea: 7 bu/ac ESN vs. UAN: 10 bu/ac ESN vs. am.nitrate: -1 bu/ac Blaylock and Tindall 2006 U.S. cornbelt 30 WHY? 25 20 15 WHY? 10 5 0 >-16-16 -12-8 -4 0 4 8 12 16 20 24 >24 Yield Difference by Using Pre-plant ESN (bu/acre)
What type of crops would you expect slow release to work better? Irrigated Warm season
Timing of nutrient uptake by crops N Uptake as percent of crop's maximum Sugar Beet 100 80 Corn 60 40 Wheat 20 0 Apr May Jun Jul Aug Sep Oct Nov Date
Timing of ESN nutrient release N Uptake as percent of crop's maximum 100 80 60 40 20 Wheat 0 Apr May Jun Jul Aug Sep Oct Nov Date Sugar Beet Corn Options for wheat? Approx % N released by typical ESN seedplaced in mid May
How does PCU work for small grains? Fall/winter pre-plant works well. PCU is in soil long enough to dissolve in time for plant need. Late winter/spring broadcast PCU does not - may dry out, release is too slow. Incorporation is important, especially late winter/spring. Blending is recommended with late winter/spring surface applied PCU.
Seed placing EEFs Can apply ~ 2 4x as much slow release product as urea directly with small grain seeds Saves on field passes fuel, labor, soil disturbance
Grain yield (bu/acre) Effect of N source applied with the seed on dryland spring wheat yield 45 40 35 30 25 20 Polymer-coated Urease inhibitor 15 10 5 0 Urea 0 25 50 75 100 125 Application rate (lb N/acre) Saskatchewan Malhi et al. 2003
Yield (bu/acre) Effect of side-banded and seed-placed N source on dryland wheat yield 45 40 Urea side-band 35 30 25 20 15 10 5 Urea seed-placed PCU seed-placed NBPT-urea seed-placed Brandt et al. 2005 Saskatchewan 0 0 20 40 60 80 100 N rate (lb/acre)
In-soil N release by 7 days (%) Handling abrasion of PCUs increases in-soil N release 35 30 ESN Seedplaced abrasion scaled equip, air boom/fan applied 25 20 average farm handling 15 10 exit retail 5 0 Beres et al. 2009 unpubl data Lethbridge, AB 20 40 60 Abrasion (%)
Plant count at emergence (per ft 2 ) Plant emergence decreases with increased N released within 7 days by seedplaced PCU 30 25 Seedplaced ESN 20 Wheat 15 10 Canola 5 0 Beres et al. 2009 in prep. Lethbridge 0 10 20 30 40 50 60 70 80 90 100 N released after 7 days (%)
Nitrogen release/uptake (% total) Some abrasion increases early release from PCU 100 60% abraded: scaled equip, air boom/fan applied 80 60 40% abraded: average farm handling 40 20 20% abraded: exit retail 0 0 7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 Beres et al. 2009 unpubl data Lethbridge, AB Cumulative days Planting date = May 9 @ 54F ESN seedplaced
Nitrogen release/uptake (% total) Some abrasion helps PCU meet wheat N demand 100 60% abraded: scaled equip, air boom/fan applied 80 60 40% abraded: average farm handling Wheat N uptake 40 20 20% abraded: exit retail ESN seedplaced 0 0 7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 Beres et al. 2009 unpubl data Lethbridge, AB Cumulative days Planting date = May 9 @ 54F Malhi et al. 2006 Saskatchewan
Nitrogen EEF and forage production Can increase mid to late season cuttings and protein, and encourage uniform growth through season Can be blended with urea to meet goal Large early crop? Season-long forage or a late cutting? Delayed release of PCU desirable PCU too slow, but urease inhibitor can help reduce urea loss Allow application flexibility - e.g. fall broadcast on coarse soil Environmentally responsible but more $
How to manage PCUs Apply several weeks before peak crop demand Incorporate into the soil or seed place Blend with conventional fertilizer Adjust rates, blends and application timing for handling abrasion
Phosphorus EEF Types Polymer coated Avail which reduces the rate of P mineral formation Limited regional research Soil P levels often above critical
Wheat response to P and Avail Karamanos et al. 2009 Alberta WHY no consistent difference? Breton Olsen P 5ppm Ellerslie Olsen P 11 ppm
Potential limitations of Avail Mechanism may have difficulty in highly calcareous soils Existing soil properties may outweigh product ability Ex: 100 lb MAP with Avail contains < 0.25 lb of organic acids the active ingredient Organic acids occur naturally in soil, and are elevated in the root zone
Additional incentive to use EEFs Alberta is close to adopting a Nitrous Oxide Emissions Reduction Protocol (NERP) which rewards use of EEFs. Other provinces may be soon adopt similar programs.
Conclusions Enhanced efficiency fertilizers (EEFs) will not increase yields and nutrient recovery under all circumstances. Improved EEFs and blending with conventional fertilizer may provide a good match between crop uptake and fertilizer availability. More EEF can be placed with the seed than conventional fertilizer, possibly saving a fertilizer pass and fuel costs. EEFs can reduce losses to the environment, especially in wet soils.
Conclusions EEFs show promise of increased yields, especially for warm season/irrigated crops. With product improvements and proper application practices, EEFs also show potential benefits for cool season crops. Additional info in: Enhanced Efficiency Fertilizers (EB0188) http://landresources.montana.edu/soilfertility Go to Fertilizer Information (will also be in MAC Proceedings)
Questions? Watrous, SK, 1920 s